• A new study found that taking vitamin D supplements was associated with lower blood pressure.
• People with obesity and high blood pressure got the best results.
• Better calcium regulation may be one of the main reasons for this effect.
• Before supplementing with vitamin D, people should get their levels tested.

According to new research published on November 12, 2024, in the Journal of the Endocrine Society, supplementation with vitamin D plus calcium may help lower blood pressure in older adults with obesity (body mass index (BMI) greater than 30).

These supplements appeared to decrease both systolic blood pressure (the top number in a blood pressure reading) and diastolic blood pressure (the bottom number).

However, they noted that more is not necessarily better when it comes to lowering blood pressure. The effect was independent of the dose administered.

The people who took part in the study had high blood pressure.

The American Heart Association states that normal blood pressure is less than 120/80.

Anything greater than a systolic blood pressure of 130 or a diastolic blood pressure of 80 is deemed to be high blood pressure.

Vitamin D supplements linked with reduced blood pressure

The study included 221 individuals ages 65 and older who were taking vitamin D supplements.

They were all classified as having overweight (BMI greater than 25).

Additionally, they had a serum 25-hydroxy vitamin D level between 10 and 30 ng/mL. Anything below 30 ng/mL is considered insufficient, while values less than 20 are classified as vitamin D deficiency.

Two doses were examined: 600 IU/day (the Institutes of Medicine’s (IOM) recommended daily dose) and 3,750 IU/day. Both groups also took 250 mg of calcium citrate.

The study participants were followed for one year.

Upon comparing the two groups, they found that the higher dose of vitamin D did not provide greater benefit than the lower one.

However, both groups experienced a statistically significant drop in blood pressure, with their systolic blood pressure dropping by 3.5 mm Hg and their diastolic blood pressure dropping by 2.8 mm Hg.

The research further found that people with obesity and low vitamin D status improved their blood pressure the most.

Why vitamin D might affect blood pressure

Reimas Geiga, MD, a medical doctor, registered dietitian, and clinical nutritionist with Glowbar LDN, explained that vitamin D can affect blood pressure in several ways.

“One of the primary ways is by aiding in calcium regulation,” he said, “which is crucial for the contraction and relaxation of blood vessels. By improving vascular function, vitamin D could help reduce blood pressure.”

Additionally, in those with obesity, there is chronic, low-grade inflammation, said Geiga. This can impair blood vessel health, contributing to high blood pressure.

“Vitamin D has known anti-inflammatory properties that may help counteract this effect,” he explained. “Moreover, people with obesity are more likely to experience vitamin D deficiency because fat cells can store vitamin D, reducing its availability to the body.”

According to Geiga, supplementation back to adequate levels can help improve vascular health and lower blood pressure.

“Additionally, vitamin D influences the renin-angiotensin-aldosterone system, a key regulator of blood pressure,” he said. “Adequate vitamin D levels may reduce the activity of this system, leading to better blood pressure control.”

Are vitamin D supplements right for you?

Given that vitamin D is easy to obtain, patients may wonder how they can apply the study’s findings to their own lives.

Dr. Rita Hawle, a clinical dietitian and nutritionist with ClinicSpots, says the first step is determining whether you are actually low in vitamin D.

“A simple blood test can reveal any deficiency that may be contributing to blood pressure issues,” she said. “If levels are low, supplements or a bit of natural sunlight exposure (when safe) can help improve vitamin D status over time.”

However, she added that vitamin D supplementation really needs to be a part of a larger strategy.

“Blood pressure responds well to a combined approach—regular exercise, a heart-healthy diet, and effective weight management are all important for long-term benefits,” said Hawle.

Additionally, while the study looked at supplementation with 600 IU and 3,750 IU doses, she advises speaking with your physician about what is an appropriate dose for you.

Vitamin D can accumulate in the human body, leading to a toxic build-up of calcium.

“This study provides encouraging insights,” Hawle concluded, “but it’s best to view vitamin D as part of a larger wellness plan, particularly for individuals managing both obesity and high blood pressure.”

Takeaway

A new study reports that older people with high blood pressure who were taking a vitamin D supplement along with calcium had lower blood pressure after a year.

The best results were experienced by people with obesity and lower initial levels of vitamin D at the start of the study.

Improved calcium regulation, lower inflammation, and reduced activity of the renin-angiotensin-aldosterone system could account for the reduction in blood pressure.

Experts recommend getting a blood test to determine if you are actually low in vitamin D and following your doctor’s advice regarding the dose you take before supplementing with it.

Supplementation should be part of a combined approach that includes a healthy diet, exercise, and weight management.